Some materials, such as the "mud" used in oil well drilling and coal slurry are normally pumped with devices which if undamped can produce cavitation or extreme pressure fluctuations which are destructive to the system through which the materials are pumped. Therefore, pulsation dampeners, such as shown in U.S. Pat. No. 3,893,485 or cavitation eliminators, such as shown in U.S. Pat. No. 4,209,041 are employed to reduce system stress. Unfortunately, in drilling operations where the "mud" is to be pumped down to a drill tip in formations which are sufficiently porous to absorb the "mud", material must be added to the "mud" to prevent its flowing through small cracks in the formation. This material also prevents the "mud" from moving in and out of the energy absorbing screen openings normally used in a pulsation dampener. When coal slurry is pumped, the coal particles tend to separate out in pulsation dampeners and cavitation eliminators to restrict their operation and become a continual maintenance problem. Therefore, there has been a need to provide a device which allows pulsation dampeners or cavitation eliminators to operate in their normal intended manner while separating them from poor flowing, corrosive, abrasive or precipitating materials.